Electroluminescent sign and method of making the same



Dec. 22, 1964 BLOCKSQN 3,161,974

ELECTROLUMINESCENT SIGN AND METHOD OF MAKING THE SAME Filed NOV. 30, 1961 Trdntparcnf Face ConducI/n Coanng -Plwsphar 0h In In:

Transpannt 4+ 11 Back INVENTOR. ELLIS 4. BLOC/(SON Attorney:

United States Patent 3 161 974 w ELECT'RGLUMINESCfiNThIGN AND METHQE) 9F MAKENG THE SALEEE Ellis A. Bloclrsnn, 3il5 (Zentenniai Ave, ewicl iey, Pa. Filed Nov. 3%, 1% Ser. No. lfiefiilll 7 (Si. ill-J39} This invention relates generally to electroluminescent signs and more particularly to electroluminescent signs having interchangeable elements structurally interlocked and electrically connected.

In my application for Electroluminescent Signs, Serial No. 50,530, filed August 18, 1960, which is now abandoned and for which this application substitutes, there is described an improved sign based on the principle of electroluminescence for illumination. The material of an electroluminescent panel generally consists of transparent sheet conductors of electricity spaced by a phosphor material serving as a dielectric between the conductive sheets. By charging the sheets with a source of electrical energy, the dielectric phosphor glows, and the panel of sheets separated by the dielectric exhibits the behavior of the condenser. The phosphor dielectric glows in various colors depending upon the chemical makeup of the phosphor, and may be fashioned in th shape of sign indicia such as letters or numerals.

Electroluminescent panels have been manufactured by a process of coating a blank with a plurality of layers at least two of which function as electrically conductive condenser plates with another serving as a dielectric of electroluminescent phosphor between the conductive layers. The panels generally include a layer of opaque material which is etched or partially removed to expose the electroluminescent dielectric layer through the transparent conductive sheet. The etching may be effected to expose the dielectric layer to view, the layer portion exposed delineating the sign indicia, or the sign indicia may be the opaque layer outlined by the electroluminescent exposed layer. The etched panel or sign must be enclosed within a housing when it is desired to be used out-ofdoors in order to withstand environment conditions such as rain.

The present invention is for an electroluminescent sign having a plurality of interchangeable indicia elements electrically connected and removably positioned in a holder. The indicia elements are made by a process wherein the electrically conductive layers and a phospor dielectric are deposited within enclosed recesses of a transparent block of insulating material with electrical leads Within the blocks in contact with the conductive layers.- When placed in the holder the leads of a block contact a bus bar within the holder, each block being connected in parallel wher by burn out of one indicia block does not interfere with the adjacent ones. The interchangeable indicia elements, or blocks, are positioned within the holder to make collectively a completed sign of the indicia. They are mechanically locked with in the holder and electrically connected to avoid short circuiting by adverse weather conditions.

An object of this invention is to provide an electroluminescent sign which is composed of interchangeable indicia elements which are rugged in construction and desirable in use under adverse weather conditions.

Another object is the provision of a method of making a sign having indicia of electroluminescent material completely enclosed in a weather tight housing.

A further object of the invention is a provide an electroluminescent sign of interchangeable elements arranged in a holder for positive electrical and mechanical connections.

A complete understanding of the invention may be had from the following detailed description of a specific embodiment thereof when read in conjunction with the appended drawings, wherein:

FIG. 1 illustrates a front elevational view of an indicia element with parts broken away to show the layered electroluminescent material between conductive coatings;

FIG. 2 is a cross-section of the indicia block taken along line IIII of FIG. 1;

FIG. 3 depicts in perspective an exploded view of the holder with end connection elements spaced from the body of the holder;

FIG. 4 is a fragmentary view of an embodiment of the invention;

FIG. 5 is an exploded perspective view of a further modification of the invention; and

FIG. 6 illustrates a rear View of an indicia block With leaf spring contacts positioned thereon.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in FIG. 1 an indicia block 11 which is of a transparent, electrically nonconductive material such as plastic. The block 11 contains within it an indicia 12, which is a dielectric of phosphor 13 being capable of glowing in brightness when placed between electricially conductive sheets or layers 14.

The layers 14 form in effect the opposed plates of a condenser with the dielectric therebetween being the phosphor 13. In the preferred embodiment of the invention the conductive layers 14 are both transparent, although the layer to the rear of the indicia block 11 may be non-transparent or opaque, it being necessary merely to see the phosphor 13 in the form of an indicia from the front of the block.

7 Electrical leads 15 are disposed in contact with the conductive layers 14 of the block 11, as best shown in i in FIG. 2. Passages 16 are drilled or otherwise formed in the block 11 to receive the electrical leads 15 into contact with the conductive layers 14, one lead to each layer, and protrude through the outer surface 17 of the block 11 to form button-like electrical contacts 18.

A holder generally designated number 19, FIGS. 3 and 5, is composed of an insulating material, and is provided with a pair of bus bars 21 recessed in opposed walls 22 of a channel portion 23 of the holder. The bus bars 21 preferably are exposed throughout their lengths within the channel portion 23 for frictional engagement with the electrical contacts 18 of'the leads 15. Since each of the opposed bus bars 21 engage only one of the electrical contacts, respectively, of a single indicia block 11 as depicted in FIG. 1, an electrical circuit is established from a bus bar 21, through a lead 15, to a conductive layer 14, and from the conductive layer 14 on the opposite side of the phosphor 13, through a lead 15, to the opposed bus bar 21 whereupon a condenser effect is accomplished. Inasmuch as each block 11 is connected similarly to the opposed bus bars 21, a parallel circuit is made with the blocks across the bus bars. Accordingly, should one interchangeable indicia block 11 become shorted out or fail to perform for other reasons the remaining blocks 11 will be unaffected and continue to illuminate.

The holder 19 includes a slueld 24 integrally formed, for example, to extend outwardly and downwardly over the channel portion 23 whereby the bus bars 21 and leads 15 of blocks ll, when positioned in the channel portion 23, are afforded additional protection against the weather, such as rain or snow. The holder 21 is substantially of a block 0 configuration in cross-section,

and a channel 25 is provided in opposed relation to the channel portion 23 so as to furnish a track or guide within which the blocks 11 are sildably received at their lower portion, with their upper portion slidably disposed in the channel portion 23. The distance between the channel portion walls 22 approximates the thickness of the blocks 11 in order that the block upper positions are frictionally but slidably held within the portion 23, and an eifective electrical connection is made between the electrical contacts 18 and the bus bars 21. The degree of clearance between the block lower portions and the channel 25 is maintained sufficiently close to maintain a frictional contact between these elements, and in the preferred embodiment, .these clearances are such that the frictional engagement between the block portions and the holder forms a water-tight seal.

At each end of the holder 19 are rectangular terminal bars 26 which have spaced bores 27 extending therethrough from front to rear. Suitable threaded fasteners 28 have shanks which are received through the bores 27 to be connected to a wall, not shown, to which the assembly of blocks 11 in holder 19 is supported. An electrical cable 2% is passed through a suitable longitudinal aperture of one of the bars 26 and is connected to contacts 31 similar in design to button-like contacts 18 of the blocks 11 as shown in FIG. 2. Lateral protuberances 32 of a cross-section similar in size and configuration to that of the blocks 11 are slidably received within the channel portion 23 and channel 25 of the holder 19, and in assembled condition, the bar contacts 31 engage electrically the bus bars 2E. The other bar 26, shown on the right of the exploded holder of FIG. 3, has an electrical conductor, not shown, which is connected to contacts 31 and which couples one of the bus bars 21 to the opposed one to complete the circuit from a source, not shown, through cable 29, contacts 31 of the .bar 26 within which the cable is terminated, the bus bars 21, and through the conductor 33.

In the modification shown in FIG. the bus bars 21 are arranged in confronting relation with one bus bar positioned within the channel portion 23, and the other within channel 25, and with the leads 15 and their re--,

spective contacts 18 in each block 11, FIG. 4, arranged for electrical engagement'with the bus bars 21. The terminal bars 26 also have their electrical contacts 31 disposed through the upper and the lower surfaces of each bar to electrically engage the respective bus bars 21. The clearances between the frictionally-engaging surfaces of the blocks 11, bars 26, and the walls 22. of the channel portion 23 and channel 25 are again such that a substantially water-tight connectionlis made between frictionally mated par-ts. The bars 26 have an overhanging cover 34 which forms an extension of the shield 24 of the holder 21 to provide further protection against weather adversities.

As an additional arangement, also depicted in FIG. 5, the improved electroluminescent sign includes bus bars 35 and 36 which are vertically spaced in parallel relation in the body 37 of the holder 19. The blocks 11 are essentially of the same construction as those described with respect to FIGS. 1, 2 and 4, the exception being the provision of leaf spring contaotors 38, 39 which couple electrically the leads 15 of the block 11 with the bus bars 35, 36. The terminal bars 26 of FIG. 5 are also of similar mechanical construction as those depicted in the embodiment of the invention illustrated in FIG. 3; however, the contactors 38, 39 are connected to the leads 15 of the cable 29, and are physically bonded to the rear face of the terminal bar 26 shown on the right-hand side of FIG. 5. The spring contacts 38' and 39 frictionally lodge the blocks 11 and the terminal bar 26 in place in the channels of the holder 19, and serve, therefore, not only as electrical connectors, but also as mechanical coupling devices to firmly position the blocks 11 on the holder 19.

The rear face of the block 11, employed in the-holder 19 shown in FIG. 5, is shown in BIG. 6. One end of each connector 38, 39 is fixed by suitable means such as add hesive bonding to the block 11 in electrical engagement with the leads 15 which are connected to the respective conductive layers 14 on opposite sides of the phosphor 13. The other end of each connector 38, 39 is in frictional sliding contact with the surface of the block ll, and the positions intermediate the ends of the connectors 38, 39 are arched or bowed outwardly. When a block 11 is slidably received within the channels of the holder 19, the resilient connectors 38, 3} are acted upon by a force which tends to flatten the arches of the connectors 38,

39. The force of the spring connection 38, 39 urges the block 11 at its upper and lower portions against the front wall of each channel thereby effecting a water-tight frictional fit between these elements.

The layers of conductive sheets 14 and the dielectric phosphor 13, FIGS. 1 and 2, are formed in a block H by casting or shaping two halves of the block with confronting indicia recesses d1. Each half-block with an indi-cia 12, PEG. 1, recessed therein is filled or coated for a portion of its depth with a suitably transparent conductive sheet 14. A groove or slot 16 is provided in the half-block face and is likewise filled with conductive transparent material to provide a lead 15 to the sheet or layer M. In the embodiment shown in FIG. 4 these slots extend through the upper and the lower surfaces of the block 11 for connection of the leads 15 and contacts 31 with the bus bars 2 6.

After the indicia recess 41 is partially filled in a halfblock, the phosphor 13 is applied for the remainder of the recess depth whereupon the face of the half-block, with the layer 1 5 subjacent the phosphor 13, is substantially planar.

Similarly, a matching half-block is provided with an indicia recess 41 which is coated on its bottom with a conductive layer 14 and which is covered with a phosphor 13. A similar slot, or aperture 16 is formed in this matching half-block for the lead 15. The two halfbloclrs are joined with their planar faces bonded by a transparent adhesive, for example, in the areas not occupied by the phosphor 13. The assembled block 11, FIGS. 1 and 2, is thus formed with the phosphor 13 sandwiohed between conductive layers 14 which are electrically connected by leads 15 to contacts 16, or 31, FIG. 4. The indicia is composed of the phosphor 13 which glows when the opposed sheets 14 are electrically energized in the manner of a condenser. The layers 14 and phosphor 13 are completely enclosed within the block material which may be plastic or ceramic, for example,

' and is capable of use with a holder 19 in environments body portion and opening thereon in confronting relation,

a plurality of transparent indicia blocks with portions slidably received within the channels with an electroluminescent indicia of phosphor between transparent conductive sheets embedded within the block and exposed on the body portion of the holder, an electrical lead connected toeach conductive sheet of the indicia and terminating on the rear face of the indicia block, a pair of resilient electrical contacts connected at their one ends to the terminals of the leads with their other ends in frictional contact with the block rear face, the contacts being arched outwardly from the rear face of the block intermediate their ends, a spaced pair of bus bars positioned on the holder body portion in electrical engagement with the arch of the contacts, the arched contacts urging the front face of the block portions within the channels into frictional engagement with one wall of the channels to effect a water-tight seal.

2. An electroluminescent sign as in claim 1 wherein a shield extends from an uppermost channel to overlie the block portions within the uppermost channel.

3. An electroluminescent sign as in claim 2 wherein a pair of terminal bars are slidably received into the channels of the holder with the indicia blocks in side-by-side relation between the terminal bars, and means within the terminal bars for connecting the bus bars electrically to complete a circuit with the leads of the blocks in parallel across the bus bars.

4. In a sign having a housing with opposed channels and a body portion for frictionally positioning electroluminescent indicia blocks in edgc-to-edge relationship thereon, the body portion having electrical bus bars exposed for electrical connection with electroluminescent blocks; an electroluminescent indicia block of a size and configuration for slideable engagement within the housing channels for mounting onto the housing, the block having an electroluminescent layer of material disposed between two conductive layers embedded within the block, leaf spring contactors fixed to one side of the block and connected electrically to the conductive layers, respectively, the leaf spring contaetors being arched at their mid-portion for contact with the bus bars arranged on the housing, and the block being received within the channels of the housing with the other side of the block being urged against the corresponding walls of opposed channels by the leaf spring contact of the electrical contactors fixed to the one side of the block.

5. In a sign having a housing with opposed channels and body portion for frictionally positioning electroluminescent indicia blocks in edge-to-edge relationship thereon, the body portion having electrical bus bars exposed for electrical connection with electroluminescent blocks; an electroluminescent indicia block of a size and configuration for slidable engagement within the housing for mounting onto the housing, the block having an electroluminescent layer of material disposed between two conductive layers imbedded Within the block, resilient contactors fixed to the block and connected electrically to the conductive layers, respectively, the contactors engaging the bus bars when the block is mounted in the housing.

6. The combination as defined in claim 5, wherein the resilient contactors are leaf spring contactors.

7. An electroluminescent sign comprising,

(a) a holder having a body portion, spaced channels on the body portion in confronting relation to each other, and spaced bus bars on the body portion electrically connected to a source of voltage, and

(b) a transparent indicia block having opposed edges disposed within the channels for slidably mounting the block on the holder and an electroluminescent indicia between transparent conductive sheets embedded within the block, an electrical lead connected to each conductive sheet terminating on the surface of the block, resilient electrical contactors mounted on the surface of the block, each being electrically connected to one of the leads, and each contactor engaging one of the bus bars when the block is mounted on the holder.

References Cited by the Examiner UNITED STATES PATENTS 1,690,003 10/28 Foerch 18-59 1,908,393 5/33 \Vinship l30 2,220,618 11/ 40 Tschopp 339-21 2,254,280 9/41 Gottheirner 339-21 2,552,249 5/51 Baxter 40130 2,685,107 8/54 Schultz 1859 2,709,863 6/55 Bevaqua 40.134 X 2,809,316 10/57 Jeges 240-2.25 2,922,912 1/ Miller 40-130 X FOREIGN PATENTS 11,703 6/ 01 Great Britain. 450,174 7/36 Great Britain. 1,198,282 6/59 France.

JEROME SCHNALL, Primary Examiner.

E. V. BURNHAM, Examiner. 

1. AN ELECTROLUMINESCENT SIGN COMPRISING A HOLDER HAVING A BODY PORTION AND UPSTANDING SPACED CHANNELS ON THE BODY PORTION AND OPENING THEREON IN CONFRONTING RELATION, A PLURALITY OF TRANSPARENT INDICIA BLOCKS WITH PORTIONS SLIDABLEY RECEIVED WITHIN THE CHANNELS WITH AN ELECTROLUMINESCENT INDICIA OF PHOSPHOR BETWEEN TRANSPARENT CONDUCTIVE SHEETS EMBEDDED WITHIN THE BLOCK AND EXPOSED ON THE BODY PORTION OF THE HOLDER, AN ELECTRICAL LEAD CONNECTED TO EACH CONCUDTIVE SHEET OF THE INDICIA AND TERMINATING ON THE REAR FACE OF THE INDICIA BLOCK, A PAIR OF RESILIENT ELECTRICAL CONTACTS CONNECTED AT THEIR ONE ENDS TO THE TERMNALS OF THE LEADS WITH THEIR OTHER ENDS IN FRICTIONAL CONTACT WITH THE BLOCK REAR FACE, THE CONTACTS BEING ARCHED OUTWARDLY FROM THE REAR FACE OF THE BLOCK INTERMEDIATE THEIR ENDS, A SPACED PAIR OF BUS BARS POSITIONED ON THE HOLDER BODY PORTION IN ELECTRICAL ENGAGEMENT WITH THE ARCH OF THE CONTACTS, THE ARCHED CONTACTS URGING THE FRONT FACE OF THE BLOCK PORTIONS WITHIN THE CHANNELS INTO FRICTIONAL ENGAGEMENT WITH ONE WALL OF THE CHANNELS TO EFFECT A WATER-TIGHT SEAL. 